This invention relates to a dentifrice composition comprising, as an abrasive, a zirconium-bonded synthetic amorphous silicate (zirconosilicate) with a zirconium content of between 0.1 to 10% by weight as ZrO.sub.2 based on SiO.sub.2 and, more specifically, it relates to a dentifrice composition which is excellent in storage-stability and can be made transparent by adjusting the refractive index of the dentifrice vehicle substantially identical with that of the zirconium-bonded synthetic amorphous silicate.
As an abrasive for dentifrice compositions, calcium secondary phosphate, calcium carbonate, aluminum hydroxide, etc. have usually been used. Since it is important for the abrasive that is has excellent storage-stability as well as high cleaning performance for teeth and good taste, abrasives possessing improved storage-stability have been demanded.
Furthermore, as an abrasive for use in the preparation of transparent dentifrice compositions, amorphous anhydrous silicas obtained through the reaction of sulfuric acid and sodium silicate have been known, as well as those anhydrous silica abrasives as described in Japanese Patent Publication No. 11159/1974, Japanese patent Laid-Open No. 75742/1974, Japanese Patent Publication No. 14935/1973, etc. Although these known silica abrasives have some advantageous features which can be used for producing transparent dentifrices, the products obtained therefrom are poor in commercial values. In general, these amorphous anhydrous silica abrasives are inferior in storage stability, especially in respect of the refractive index. Therefore, it will be happen that the transparent toothpastes having the conventional silica abrasives blended therein are deteriorated in terms of transparency in the storage test. Furthermore, the conventional amorphous anhydrous silica abrasives can not be blended in a great amount because they generally have a large liquid absorption and it is difficult to prepare the amorphous anhydrous silica abrasives so as to reduce their absorption. In order to obtain a transparent dentifrice having a desired viscosity at a desired abrasing level by using the conventional silica abrasives, it is necessary to condition the composition of the transparent dentifrice vehicle. Therefore, conventional amorphous anhydrous silica abrasives involve a problem with respect to the blendability.